1. Field of the Invention
The invention relates to a procedure for optimizing the processing of cutting material, such as textiles, leather, technical fabrics and the like and particularly for interlocking the cutting patterns before the automatic cutting process. The invention takes into account any defective spots or other variations on the surface of a possibly particularly large-surface cutting material. The cutting patterns are stored, after having been set up in a CAD system or the like, in a computer unit as contours of the cutting material. The contours can be called from the computer unit and be positioned on the cutting material by means of a control unit. Their final position are transmittable to the cutting unit.
Thus, for instance, any leather skin, from which forms are cut to produce products from real leather (e.g., shoes, bags, furniture, garments) is a single part with areas of different quality, defects, knots and diverging colours. About the same can be said of textiles and other fabrics, especially if these are patterned.
2. Description of Prior Art
So far, cutting patterns in the form of punching dies or templates were quite frequently placed by hand on the leather surface or the like to ensure the best possible use of the material while taking into account all the properties of the material (e.g, defects, differences of colour, thickenings). Subsequently, the cutouts are either cut out by hand with a drawing knife, or punched out if a punching die is used. Automatic cutting devices, such as so-called cutters, cannot be used for such a working process.
An experienced leather cutter is required to perform preparatory work with these methods in order to achieve the necessary quality and optimization of the material to be cut. A great part of his work and time is used for heavy craftman's work. For instance, placing of the templates and punching dies, punching and cutting with the drawing knife. This work is rather laborious and far from being effective.
In addition, the use of punching dies is only appropriate if long pattern cycles permit the longest possible use of the same dies which are rather expensive. The high costs of approximately DM 250,000 and more per year for manufacturing and maintaining such tools does not justify their use for short pattern cycles. Moreover, handling of the punching dies is time consuming and requires considerable exertion. Attendant circumstances to the handling of such dies are damages to health and interruptions of work.
In OE-PSS E 33 746 B (EP 01 65 890), a procedure and a device are disclosed for the reciprocal arrangement of cutting patterns on a pad for drawing and/or cutting. The coordinates of diverse templates to be cut out are stored in a main memory and are displayed on a monitor. They are projected by means of a video projecting unit directly from the monitor onto the material to be cut which lies on a pad. Such templates can be moved on the monitor via the video projecting unit using a control unit connected to the computer until their final position has been reached. These positions are then displayed on the monitor. When the contours have been interlocked, the cutting operation is triggered.
Such a procedure is only applicable for small templates and hence for small patterns since their size is limited by the dimensions of the screen of the monitor. An enlargement of what is on the screen is not possible because the resolution of lines of the video projector will lead to blurs. The contours of cutting patterns will thus become unrecognizable on the leather skin or the like.
A similar procedure and a device for optimizing the cutting of material was disclosed in DE-PS 36 27 110, which also uses a computer and a monitor to display the contours to be cut. Taking into account any defective spots of the material to be cut, these contours are projected on the cutting material by an electronic projecting unit of great light transmitting capacity as enlarged contours in original size as compared to the monitor image. The total area of the cut obtained is calculated after positioning and then put in a relation to the area of the material to be cut. The automatic cut is performed only when a specific degree of utilization has been reached.
This proposed solution for optimizing the cutting of material has some drawbacks too. A monitor image is again projected by video. Instead of an electronic projector of great light transmitting capacity, a laser so scanner system could be used, which in turn has some disadvantages. For example, the rather slight spot velocity of the mechanical scanner system and consequences of the rather slight spot velocity. Here again, the operating personnel have to move to and from between the monitor and the working area and interlock the cutting patterns on the screen. In addition, this process requires that both the shape and the condition of the leather skin or the like should be completely visible on the monitor which, however, cannot be fully achieved. Besides, there are fixed limits of tolerance with such a procedure which cannot be exceeded and a considerable amount of devices are required too.
In fact, such activities can still be carried out much better and more effectively by man, as one has not yet succeeded to assess the quality of a leather skin or the like by projecting any parts at the same time on the skin, which would be indispensable. None of the known systems enables the operating personnel to work directly on the cutting material.
These drawbacks are overcome by the present invention.